1st computer virus is written, January 30, 1982

A 15-year-old boy on winter break from high school wrote what is considered to be the first large-scale, self-spreading personal computer virus on January 30, 1982.

Richard Skrenta’s “Elk Cloner” was 400 lines long and disguised as an Apple boot program. (See Skrenta's current day photo, right)

What has since been described by its author as "some dumb little practical joke,” the virus attached itself to the Apple DOS 3.3 operating system and spread by floppy disk.

Skrenta was already known as a video game prankster among his friends. He often shared his gaming software after altering the disks in a way that would interrupt the game with taunting messages. As such, some of his friends had stopped swapping games with him.

To continue pranking, Skrenta had to find a way to alter floppy disks without physically touching them. This lead him to create what is now known as a boot sector virus through Elk Cloner.

Skrenta left Elk Cloner residue in the operating system of his school's Apple II. Any student who did not do a clean reboot with their own disk could then be touched by the code.

An infected computer would display the following short poem on every 50th boot:

Elk Cloner: The program with a personality It will get on all your disksIt will infiltrate your chipsYes, it's Cloner!It will stick to you like glueIt will modify RAM tooSend in the Cloner!

Considered very contagious, Elk Cloner successfully infected the floppies of most people Skrenta knew. That was considerably easy to do as in 1982 personal computing was still new and most were not wary of viruses, nor were virus scanner programs available.

Elk Cloner could be removed, but it required an elaborate manual effort.

Skrenta went on to graduate Northwestern in 1989 with a BA in computer science. According to Skrenta’s LinkedIn profile, he is now CEO of search-engine start-up Blekko. One LinkedIn recommendation for Skrenta reads: “Fear this man and his army of cyborgs.”